Cathode disintegration



"the cathode at the required temperature.

Patented July l4, 1936 OFFlCE @ATHODF: DI SINTEGBATION Paul Alexander, Brussels, Belgium, assignor to La Dispersion Cathodique (en abrg Disca) S. A...

Brussels, Belgium 1 No Drawing. Application November 1, 1934, Serial No. 751,091. In France October 16, 1934 This invention relates to improvements made in the processes of cathode disintegration.

One of the objects of the present invention is to allow of effecting the cathode disintegration of metals in a rapid and economic manner; more particularly, the present invention allows of depositing by cathode disintegration certain metals which could not be deposited at all so far or only in an unsatisfactory manner by the same method.

The invention applies more particularly to the cathode disintegration of metals belonging to the groups of iron and tungsten (periodic systems), such as Fe, Ni, Co, Cr, W, Mo.

The invention also allows of effecting the cathode disintegration at a higher pressure than that which was necessary before.

It has now been recognized that the chemosorption and the active adsorption of gases by a metal to be deposited by cathode disintegration are intimately connected with the difliculty of ble of reacting chemically with the liberated gas or gases.

The liberation of sorbed gas is effected preferably with a highly heated cathode. The temperature at which the cathode should be heated vdepends on the metal to be deposited. on the chemical nature of the filling gas, and on the nature of the sorbed gas.

Any suitable means may be used for heating For instance. use may be made of the same current which will afterwards eifect the disintegration of thecathode, or an independent heating of the cathodes may be used.

During the escape of the sorbed gas or gases, the disintegration of the cathode may be prevented by all suitable means, for instance by inserting a'separating surface between the electrodes and the objects to be covered with metal, or by any other means.

It is possible to lower the temperature at which the sorbed gases are liberated by producing or by increasing the degree of ionization of the filling gas. This may be accomplished by all suitable means, such as auxiliary electrodes.-

X-rays, radium, or by the electrodes for the cathode disintegratiometc.

Example 1.-For effecting the cathode disintegration of cobalt, use is made of cathodes-consisting of bands of cobalt having a width of 4 mm. and a thickness of 2 mm. As a filling gas, hydrogen is used at a pressure of 0.36 mm. of

sorbed gas (oxygen) is effected during about one gration of molybdenum, use is made of cathodes minute. The cathode disintegration is afterwards effected under a lower voltage of 2000 volts during about five minutes. A metal. layer of about 40 n illimicrons is obtained.

Example 2.-For effecting the cathode disintemade of molybdenum wire and having a diameter of 0.8 mm. As filling gas, hydrogen is used at a pressure of 0.4 The cathodes are first heated at a temperatureof 1200 C. and-the liberationof sorbed gas is then effected during about 2 minutes. Afterwards the cathodes are disintegrated at a lower voltage of 1900 during about 4 minutes for producing a layer of about 40 millimicrons. I

It is understood that the above figures are iven merely by way of example; they may vary according to the shape and dimensions of the electrodes, according to the nature of the filling gas, etc. 4

The present invention applies naturally to all the applications of cathode disintegration for the manufacture of heating units, for the manufacture of electric resistances, of mirrors, etc.

As said above, the temperature at which the cathodes should be heated for producing the escape of the sorbed gas or gases, depends on the nature of the metal itself. In the case of certain metals the temperature may reach the white heat. In the case of platinum, tungsten, etc., the tem-.' perature exceeds 1300 C. a

I claim:

- 40 1. A process for cathode disintegration in a sorption, in-an atmosphere of a gas capable of reacting with the gas of said film, which comprises first ionizing said atmosphere and preheatingthe cathode to atemperature and for a time suflicient to liberate said gas film. and then disintegrating the film-tree cathode.

3. A process for cathode disintegration in a gaseous atmosphere of a cathode formed or a metal having a gas film bound thereto by chem osorption or active adsorption. which comprises first ionizing said atmosphere and preheating the cathode to a temperature and for a time sumcient to liberate the gas film therefrom by passing a current of electricity thcrethrough, and then disintegrating the film-tree cathode by the same current.

4. A process for cathode disintegration in a gaseous a mosphere or a cathode formed or a metal having a gas film bound thereto by chemosorption or active adsorption, which comprises aoa'aaso first ionising said atmosphere and preheating thecathodetoatemperature andforatime sufllcient to liberate the gas film therefrom by a source of heat other than the disintegrating current, and then disintegrating the film-tree cathode by passing an electric current therethrough.

5. A process of cathode disintegration of a cathode formed or a metal having an oxygen film bound thereto by chemosorption or active adsorptioh, in an atmosphere of hydrogen, which comprises first ionizing said hydrogen atmosphere and preheating the cathode to a temperature and for a time sufiicient toliberate said gas film, and then disintegrating the film-tree cathode.

PAUL ALEXANDER. 

